Patent GB-237942-A (GB)
Title: Improvements in or relating to vacuum tube illuminating devices
IPC: H05B41/44
Filed: 1924-03-28
Abstract: 237,942. Robertson, J. R. March 28, 1924. Illumination, changing advertisements by controlling; moving-apparatus combined with vehicles. - A plurality of vacuum tubes aremounted on a frame or support which also acts. as or supports a conductor, each tube having the form of a letter, design, sign, or part thereof; each tube is compound, i.e. consists of two or more tubes d, e, Fig. 2, one within another with or without electrodes to each tube, or of two or more sealed tubes t, Fig. 4, placed end to end with or without intermediate electrodes z. The vacuum tube shown in Fig. 2 consists of an inner tube d having an expansion chamber d' at one end of larger diameter. Surrounding the tube d' is a coaxial tube e, 'which may be formed with an expansion chamber e<1> by reducing the diameter of the inner tube d at one end d' and sealing to the extremity of the chamber e<1>. Alternatively, the inner tube d may have a chamber d<1> at each end, the external tube having no expansion chamber. Electrodes d<2>, e' are provided for the inner tube d, electrodes e<2>, d<3> also being provided for the outer tube e. One terminal of each tube d, e, for example, the terminals d<3>, e' may be earthed, and the other terminals d<2>, e<2> of a set of such tubes mav be connected to the contacts of revolving switches connected to the secondary winding of a step-up transformer and so arranged that the various tubes are caused to glow in any desired sequence. The revolving switches may be driven by the engine of a motor-car, aeroplane, &c. carrying the sign &c. The vacuum tube t shown in Fig. 4 consists of several sections, preferably filled with different gases so as to glow with different colours and either provided with end electrodes m or formed without electrodes. Intermediate electrodes z may be provide between the sections. A set of such tubes, made into the form of letters c, Fig. 1, may be mounted on an insulating board or slab b, the tubes being without electrodes. High-tension conductors a', a<2> are mounted on the board b, the tubes c being- caused to glow by the electrostatic field betweenthese conductors, which conductors may be given an ornamental appearance so as to appear to constitute the border of a frame. A number-plate for a motor-car may be similarly formed, the conductors a<1>, a<2> being connected to the secondary winding of a transformer in the circuit of the magneto. The tubes are preferably filled with bromine or neon. The separate tubes may be connected respectively in series with the sparking-plugs of the engine. Vacuum tubes t, Fig. 5, of the type shown in Fig. 4, may be suspended from a ring-shaped electrode o by conductors t<2> on which coloured glass beads may be strung to produce an ornamental effect. The electrode o is connected to the secondary winding of a small transformer contained in a disc n adapted to fit an ordinary lamp-holder. The vacuum tubes may be of flat shape, the different sections being formed as parts of a picture, so as to produce an effect resembling stained glass. The edges may be silvered, metal-coated, or plated, or may be painted with metallic paints. Illuminating beads or tubes mav be attached to dresses &c. used for stage ballets and dancing effects, connection to a source of high-frequency current being made either by an invisible wire or through metal strips or plates set in the stage floor and metal contacts on the dancer's shoes. Colour changes may be effected by switches controlled by the dancers. Thorium, uranium, or other radioactive minerals &c. may be incorporated in either of the double vacuum tubes or in their electrodes. Advertising devices as previously described may be immersed in coloured liquids or embedded in translucent objects such as cakes of soap. Glass of special composition which becomes luminous under the action of ultra-violet radiation may be used. According to the Provisional Specifications, flashing may be effected by thermo cut-out switches, or by connection to the different phases of a polyphase supply; the silver-deposited electrodes may form a mirror or may be in the form of letters; tubes may be illuminated by projecting thereon an ultra-violet ray in the form of an advertisement or design, as described in Specification 214,274, [Class 39 (i), Electric lamps, Arc &c.] ; tubes may be illuminated by radiotelegraphic means; for low-tension supply a tube having one central axial electrode and a second helical electrode round the walls may be employed.